Method for controlling obesity using minimally invasive means

ABSTRACT

Methods for controlling obesity using minimally-invasive procedures including introducing embolic crystal particles that are naturally occurring and mostly non-toxic salts into the arterial capillaries feeding the sections of the stomach where the appetite inducing hormone, ghrelin, is produced to limit the blood flow to the region reducing appetite; introducing a virus vector or antisense oligonucleotide to inhibit the production of ghrelin and reduce the appetite; and introducing a soluble embolic particle with a virus vector or antisense oligonucleotide which will inhibit the flow of blood initially and then dissolve and release the inhibit vector to the region, generating ghrelin to control the appetite.

BACKGROUND

1. Field

The invention relates to methods for controlling and treating obesityusing non-surgical means and specifically by reduction of or inhibitionof the production of ghrelin the apitize generating hormone.

2. Related Art

Obesity has become an epidemic problem in Western societies contributingto several disease processes including metabolic diseases, hypertension,and cardiovascular disease. Adipogenesis is defined as the formation offat or fatty tissue, the development of fat cells from pre-adipocytes.Obesity is a severe chronic syndrome characterized by excessiveaccumulation of fat. Patients with abdominal obesity are often prone todiseased conditions such X-syndrome (insulin resistant diabetes, Type 2diabetes, hypertension, and disorders of lipid metabolism), andabdominal obesity becomes one of the potent risk factors of earlyarteriosclerosis, ischemic heart disease, and cerebrovascular disease.

Urbanization of countries' populations with associated sedentarylifestyles and intake of rich foods on a normal basis has led to anincrease in obesity in the general population. The chronic obese segmentof the population now stands close to 30% in the US and other developedcountries. This has created an increase in associated illnesses leadingto increase in health care costs across these countries.

There are multiple aims for treatment for obesity. A first aim is toreduce weight by burning excessive fat or reduce absorption of food thatcan be converted to fat; a second aim is to improve a metabolicimbalance in patients.

Today, there are a number of surgical methods for treatment of obesity,such as an implantable balloon device to stretch the stomach wall andsimulate satiety during eating, thereby reducing the amount of foodintake of the patient. Another surgical method used to reduce foodintake and absorption requires reducing the size of the stomach itselfby using gastric band with or without electrical stimulation, removal ofpart of the intestines to reduce food absorption, etc. Though thesesurgical methods have been available for control of obesity for sometime now, the number of even acutely obese patients who opt for suchprocedures have been very small and hence the success of controllingobesity in the general population by these methods have been limited.

Alternate treatment by medication has also been proposed to limit andcontrol food intake and absorption. Most of these medications have sideeffects that are not acceptable to the using public. Hence, this type oftreatment has also not been too well received.

Since obesity has been recognized as a major problem, other methods forcontrolling it, that are more acceptable to the public have been underinvestigation and need to be identified. A large number of studies havefocused on use of chemical agents and gene identification aspects tocontrol obesity. Others have looked at nerve excitation and sensationremoval as treatment for obesity.

Accordingly, what is needed is a non-surgical way, that is minimallyinvasive, to treat obesity that is acceptable to the obese populationand can be easily implemented.

SUMMARY

The following summary of the invention is included in order to provide abasic understanding of some aspects and features of the invention. Thissummary is not an extensive overview of the invention and as such it isnot intended to particularly identify key or critical elements of theinvention or to delineate the scope of the invention. Its sole purposeis to present some concepts of the invention in a simplified form as aprelude to the more detailed description that is presented below.

In accordance with one aspect of the invention, a method of treatingobese patients is disclosed that includes delivering embolic particlesto targeted ghrelin production sites.

The embolic particles may be virus vectors embedded in the embolicparticles. The embolic particles may be antisense inhibitors embedded inthe embolic particles. The embolic particles may reduce blood flow atthe targeted ghrelin production sites. The embolic particles may reduceblood flow at the targeted ghrelin production sites and the virusvectors may sustain reduced production of ghrelin. The embolic particlesmay reduce blood flow at the targeted production sites and the antisenseinhibitors sustain reduced production of ghrelin. The embolic particlesmay be magnesium phosphate. The embolic particles may be calciumdi-hydrogen phosphate. The embolic particles may be potassiumdi-hydrogen phosphate.

The embolic particles may be delivered using a percutaneously introducedcatheter guided to the targeted ghrelin production sites using animaging technique. The imaging technique may be selected from the groupconsisting of x-ray fluorescence or ultrasound tracking.

The size of the embolic particles may be between 300 and 500 microns.

In accordance with another aspect of the invention, a method of treatingobese patients is disclosed that includes delivering modified virusvectors to targeted ghrelin production sites.

The method may further include delivering embolic particles to thetargeted ghrelin production sites.

The virus vectors may be delivered using a percutaneously introducedcatheter guided to the targeted ghrelin production sites using animaging technique.

The imaging technique may be selected from the group consisting of x-rayfluorescence or ultrasound tracking.

In accordance with a further aspect of the invention, a method oftreating obese patients is disclosed that includes delivering modifiedantisense oligonucleotide to targeted ghrelin production sites.

The antisense oligonucleotide may include shRNA, and the method mayfurther include using synthesized SiRNA to generate the shRNA.

The antisense oligonucleotide may be ghrelin-O-aclytransferase (GOAT).The method may further include delivering embolic particles to thetargeted ghrelin production sites.

The virus vectors may be delivered using a percutaneously introducedcatheter guided to the targeted ghrelin production sites using animaging technique. The imaging technique may be selected from the groupconsisting of x-ray fluorescence or ultrasound tracking.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated into and constitute apart of this specification, illustrate one or more examples ofembodiments and, together with the description of example embodiments,serve to explain the principles and implementations of the embodiments.

FIG. 1 is a block diagram showing a method for controlling obesity inaccordance with one embodiment of the invention.

FIG. 2 is a block diagram showing a method for controlling obesity inaccordance with one embodiment of the invention.

DETAILED DESCRIPTION

Obesity has been identified as a contributing factor to many of thediseases of the present day. Obesity is a medical condition in whichexcess body fat has accumulated to the extent that it may have anadverse effect on health, leading to reduced life expectancy and/orincreased health problems. Obesity is a leading preventable cause ofdeath worldwide, with increasing prevalence in adults and children, andauthorities view it as one of the most serious public health problems ofthe 21st century. Obesity increases the risk of many physical and mentalconditions. Excessive body weight is associated with various diseases,particularly cardiovascular diseases, diabetes mellitus type 2,obstructive sleep apnea, certain types of cancer, and osteoarthritis. Asa result, obesity has been found to reduce life expectancy. Thesediseases are either directly caused by obesity or indirectly relatedthrough mechanisms sharing a common cause such as a poor diet or asedentary lifestyle. Current solutions are mostly invasive in nature andhence have had a very difficult time finding acceptance from the obesecommunity.

Leptin and ghrelin are considered to be complementary in their influenceon appetite, with ghrelin produced by the stomach modulating short-termappetitive control (i.e., to eat when the stomach is empty and to stopwhen the stomach is stretched). Leptin is produced by adipose tissue tosignal fat storage reserves in the body, and mediates long-termappetitive controls (i.e., to eat more when fat storages are low andless when fat storages are high). While these appetite mediatingadipokines are produced peripherally, they control appetite throughtheir actions on the central nervous system. In particular, they andother appetite-related hormones act on the hypothalamus, a region of thebrain central to the regulation of food intake and energy expenditureand include the lateral hypothalamus and ventromedial hypothalamus, thatare the brain's feeding and satiety centers. In some recent studies theeffect of ghrelin has been found to have a significant impact on theeating habits and development of obesity in individuals.

Embodiments of the invention are directed to methods for reducing orinhibiting the production of ghrelin and other similar compounds in thehuman body, thereby reducing the short term urge for food intake tocontrol obesity. Embodiments of the invention also reduce or inhibitleptin production. The disclosed methods are minimally invasive andhence are expected to be more acceptable as treatment by a wider groupof obese patients.

Embodiments of the invention are directed to minimally invasive methodsthat might be more acceptable to the obese population for the treatmentof obesity. In one embodiment, embolic particles of naturally occurringand non-toxic magnesium phosphate, calcium di-hydrogen phosphate and/orpotassium di-hydrogen phosphate are introduced into the arterialcapillaries feeding the sections of the stomach where the appetiteinducing hormone, ghrelin, is produced to limit or inhibit the bloodflow to the region. This reduces or destroys the cells that produceghrelin and thereby reduce the short term appetite. Over a short periodof time alternate capillaries will re-establish blood flow to the regionbut the destroyed cells will not re-generate within such period,enabling control of appetite and hence obesity of the individual.Typical introduction method for the embolic particles is by means of acatheter of the appropriate size, percutaneously introduced and guidedusing xray fluorescence or ultrasound tracking methods to the location.Once at the location the embolic particles are released into the bloodstream in appropriate quantities required to block the blood flow to theregions generating ghrelin.

These magnesium phosphate, calcium di-hydrogen phosphate and potassiumphosphate particles have multiple advantageous for bariatricembolization over other similar embolic particles. For example, in thecase of potassium and calcium salts, the PH value of the solution may beadjusted using magnesium hydroxide or calcium hydroxide.

In particular, they are easily manufacturable in the required sizes foruse as embolic particles, typically in the range between about 50 to 700micro meters in size. In one particular embodiment, the embolic particlesize is any value or range of values between about 300 to 500micrometers.

Magnesium phosphate, calcium di-hydrogen phosphate and potassiumdi-hydrogen phosphate are also a naturally occurring compound in naturethat is non-toxic in human applications. This reduces any adversereactions to the use in treatments of the embolic particles.

Additionally, the structure of the magnesium phosphate, calciumdi-hydrogen phosphate and potassium di-hydrogen phosphate particles aremore regular and smooth than some of the other particles used in otherapplications as embolic particles. These particles, due to their shape,are able to reduce unnecessary trauma to the arterial walls of thevessels through which they are introduced.

Adding magnesium to the embolic particle as magnesium phosphate oradjusting the PH of the embolic particle forming solution by addingmagnesium hydroxide provides additional advantages. Magnesium has thecharacteristics of enhancing the formation of capillaries. This allowsfor re-establishment of blood flow to the treated regions of the bodyfaster for enabling recovery of the required functionality.

Magnesium phosphate is a compound that typically dissolves over time andcan be used as a source inhibit vectors that are released over time intothe blood stream feeding the target cells. Calcium di-hydrogen phosphateon the other hand is more stable and remains in system for a longertime, reducing the re-growth of the targeted cells.

In another embodiment, a virus vector or an antisense oligonucleotide isintroduced to inhibit the production of ghrelin in conjunction with theembolization and reduce the appetite. The use of virus vectors,antisense oligonucleotide and Clustered Regularly Interspaced ShortPalindromic Repeats (CRISPRs) have been used in the past for enhancingor inhibiting the production of various proteins or nucleic acid. It ispossible to design a targeted delivery of the virus vectors or antisenseoligoneucleotide to the target location within a gene to replacetargeted segments of the gene associated with production of ghrelin. Thesilencing, or inactivation, of the targeted generation can be effectedby cleaving the targeted nucleic acid sequence or replacement of thetargeted RNA sequence by the alternate gRNA sequence. The delivery ofthe vector itself can be accomplished similar to the method of deliveryof the embolic particles. A catheter of the appropriate size ispercutaneously introduced and guided using x-ray fluorescence orultrasound tracking methods to the treatment location. Once at thelocation, the virus vectors are released into the blood stream inappropriate quantities enabling substitution of the target RNA segmentin the gene at the location to inhibit or stop production of ghrelin.Introducing a soluble embolic particle containing a virus vector or anantisense oligonucleotide which will inhibit the flow of blood initiallyand then dissolve, releasing the inhibit vector or antisense to theregion generating ghrelin, provides a longer term control of ghrelingeneration and control of the patient's appetite.

In some embodiments, short RNA strands may be used to achieve the resultof suppressing the ghrelin production.

Small interfering RNA (siRNA) is an intermediate step in the RNAinterference (RNAi) pathway. RNAi is a natural process the cells use toturn off unwanted genes. The siRNA is a double strand of 20 to 25molecules that can bind to an RNA-induced silencing complex RNA. ThissiRNA cleaves the gene such that it stops producing the unwantedprotein. The siRNA may be synthesized and used as a ghrelin inhibitor.

Similarly, a DNA construct may be delivered to the nucleus of a cellusing a virus to enable the target cells to produce a short hairpin(shRNA) which can act as the inhibitor to the target protein. This shRNAmay be also be used as a ghrelin inhibitor.

In another embodiment, the use of the embolic particle with the releaseat the target site of the inhibit vector are combined. The combinationis advantageous because it provides a more appropriate and long termsolution. In this embodiment, an embolic particle that dissolves overtime is embedded within the inhibit vector or antisense oligonucleotide.The embolic particle is initially used to reduce the blood flow to thetarget location. This reduces the production of ghrelin as describedabove. Over time, the embolic particle dissolves away releasing theinhibit vector or antisense oligonucleotide into the target area insmall doses to limit the regeneration and production of ghrelin over along period of time. In one particular embodiment, the antisenseoligonucleotide is ghrelin-O-acyltransferase (GOAT).

The use of potassium di-hydrogen phosphate as the base salt has theadvantage that the dissolution rate of the crystal (embolic particular)during use is slow, enabling slow release of any inhibit vectorsembedded therein while providing long term embolization of the region.The use of calcium di-hydrogen phosphate as the embolic particledissolves away faster than the potassium di-hydrogen phosphate and ituse is limited to short term embolization of the region followed bydeliver of inhibit vectors to the correct location.

In each of the embodiments described above, the short term appetite isreduced with a direct impact on the obesity of the person treated.Although the techniques for treatment of obesity discussed herein aredirected to the control of production of ghrelin, it will be appreciatedthat the treatment techniques disclosed herein may also be used for thelong term appetite inducer leptin to further improve the treatment ofobesity.

An exemplary procedure for use of embolic particles for obesitytreatment (Bariatric embolization) is described briefly with referenceto FIG. 1. It will be appreciated that the embolic particle may or maynot contain inhibit vectors attached to the surface or embedded withinto allow for slow release as the particle dissolves, as described above.

The process begins by preparing the embolic particles and choosing theright size range of the particles for use (block S1001).

The process continues by preparing the colloidal solution of embolicparticles, with iodinated contrast material added for contrast, forbariatric embolization of the patient (block S1002).

The process continues by puncturing the groin at the common femoralartery (or puncture the radial artery in the wrist) for introduction ofa catheter, with ultrasound and fluoroscopic guidance (block S1003).

The process continues by introducing a pigtail catheter into the aortawith aortagram (AP and lateral projection) for control (block S1004).

The celiac artery is selected using a reverse curve catheter with aguide wire and a celiac angiogram is performed to get correct data onthe access to the left gastric artery branch of the celiac artery (blockS1005).

The left gastric artery branch of the celiac artery is selectedtypically using a microcatheter (block S1006). This can be done with orwithout selection of this artery using the reverse curve catheter. Itwill be appreciated that a 0.014 inch guide wire may used in addition toor as a substitute for the microcatheter.

The process continues by using dilute iodinated contrast and using acolloidal form of embolic particles prepared to embolize the leftgastric artery branches using the particles to limit or stop productionof ghrelin and treat the patient for obesity (block S1007).

The process continues by removing the catheters and obtaining hemostasisusing normal steps employed for the purpose (block S1008).

An exemplary preparation process for embolic particles with embeddedembolization vectors and without embolization vectors is brieflydescribed with reference to FIG. 2.

The typical chemical compound for creation of the embolic particle, withwhich the process is explained, is potassium di-hydrogen phosphate(KH₂PO₄) or calcium di-hydrogen phosphate (CaH₂PO₄). The solution of(KH₂PO₄) or (CaH₂PO₄) in water has a PH value near 4.2 which is not verysuitable for bariatric embolization. Though KH₂PO₄/CaH₂PO₄ use isdetailed, magnesium can be used instead as the base salt for making theembolic particle. Since magnesium provides advantages of capillaryre-growth etc., adding magnesium hydroxide to get the PH value of theprepared solution to the range of 5.5 to 6, which is suitable forbariatric embolization, is typically preferred. As shown in FIG. 2, theprocess for preparation of the embolic particle is as follows:

The process begins by providing a powder potassium or calciumdi-hydrogen phosphate (KH2PO4 or CaH2PO4) salts in solution (blockS2001). This solution typically has a PH value in the range of 4.2 to4.7, which is not suitable for use in bariatric embolization.

The process continues by making a saturated solution of the salt inwater heated to 80 to 90 Fahrenheit while stirring continuously to makethe salts dissolve fully (block S2002).

The process continues by mixing magnesium hydroxide (MgOH) solutionpreferably (or calcium hydroxide solution) to the above preparedsolution to change its PH value to between 5.5 and 6.0 which is suitablefor bariatric usage (block S2003). Mixing magnesium hydroxide to thesolution has the effect of replacing some of the potassium or calcium inthe solution with magnesium, in addition to changing the PH value.

As an optional step, any vectors that need to be incorporated into theembolic particles are added into the solution in quantitiespredetermined to be appropriate to get the concentration of the inhibitvectors in the embolic particles (block S2004).

The resultant solution is cooled at a rate sufficient enough to generatecrystals typically in the range of 300 to 600 micron size from thesolution (block S2005).

The crystals are tumbled/ground to remove the rough edges and achieve amore spherical form, in order to prevent trauma to the arterial wallsduring use (block S2006).

The crystals are sieved to optimize the size range, typically a ragewithin 300 to 500 microns, (the exact value or range can vary with thepatient and the treatment parameters) required for the bariatricembolization application (block S2007).

A colloidal solution of the embolic particles with dilute iodinecontrast solution is prepared and used for bariatric embolization (blockS2008). For example, the process of FIG. 1 can be used for the bariatricembolization; it will be appreciated that other processes may be usedfor the bariatric embolization.

Even though the techniques for treatment of obesity discussed herein aredirected to the control of production of ghrelin, similar treatments mayalso be provided for the long term appetite inducer leptin to furtherimprove the treatment of obesity. It is understood that it is possibleto use modifications of the methods disclosed to treat other problems inhuman patients that are treatable by inhibition or increase of specificprotein production by cells in the body. Such modifications of thedisclosed method, which will be well understood by practitioners of theart, though not explicitly covered, are also covered by thisapplication.

As will be understood by those familiar with the art, the invention maybe embodied in other specific forms without departing from the spirit oressential characteristics thereof. Likewise, the particular naming anddivision of the members, features, attributes, and other aspects are notmandatory or significant, and the mechanisms that implement theinvention or its features may have different structural construct,names, and divisions. Accordingly, the disclosure of the invention isintended to be illustrative, but not limiting, of the scope of theinvention.

While the invention has been described in terms of several embodiments,those of ordinary skill in the art will recognize that the invention isnot limited to the embodiments described, but can be practiced withmodification and alteration within the spirit and scope of the appendedclaims. The description is thus to be regarded as illustrative insteadof limiting. There are numerous other variations to different aspects ofthe invention described above, which in the interest of conciseness havenot been provided in detail. Accordingly, other embodiments are withinthe scope of the claims.

The invention has been described in relation to particular examples,which are intended in all respects to be illustrative rather thanrestrictive. Those skilled in the art will appreciate that manydifferent combinations will be suitable for practicing the presentinvention. Other implementations of the invention will be apparent tothose skilled in the art from consideration of the specification andpractice of the invention disclosed herein. Various aspects and/orcomponents of the described embodiments may be used singly or in anycombination. It is intended that the specification and examples beconsidered as exemplary only, with a true scope and spirit of theinvention being indicated by the following claims.

1. A method of treating obese patients comprising: delivering embolicparticles of a naturally occurring compound to arterial capillariesfeeding targeted ghrelin production sites of an obese patient, thenaturally occurring compound selected from one of a magnesium phosphate,a calcium di-hydrogen phosphate or a potassium di-hydrogen phosphate,wherein the embolic particles dissolve over time when introduced intothe arterial capillaries, and wherein the embolic particles reduce bloodflow to the targeted ghrelin production sites.
 2. The method of claim 1,wherein the embolic particles comprise virus vectors embedded in theembolic particles such that the virus vectors are released as theembolic particles dissolve over time.
 3. The method of claim 1, whereinthe reduced blood flow reduces production of ghrelin.
 4. The method ofclaim 2, wherein virus vectors sustain reduced production of ghrelin. 5.The method of claim 1, wherein the embolic particles comprise antisenseinhibitors embedded in the embolic particles such that the antisenseinhibitors are released as the embolic particles dissolve over time. 6.The method of claim 5, wherein the antisense inhibitors sustain reducedproduction of ghrelin.
 7. The method of claim 1, wherein the embolicparticles comprise magnesium phosphate.
 8. The method of claim 1,wherein the embolic particles comprise calcium di-hydrogen phosphate. 9.The method of claim 1, wherein the embolic particles comprise potassiumdi-hydrogen phosphate.
 10. The method of claim 1, wherein the embolicparticles are delivered using a percutaneously introduced catheterguided to the targeted ghrelin production sites using an imagingtechnique.
 11. The method of claim 10, wherein the imaging technique isselected from the group consisting of x-ray fluorescence or ultrasoundtracking.
 12. The method of claim 1, wherein the size of the embolicparticles is between 300 and 500 microns.
 13. The method of claim 2,wherein the virus vectors embedded in the embolic particles comprisemodified virus vectors.
 14. (canceled)
 15. The method of claim 0,wherein the virus vectors embedded in the embolic particles aredelivered using a percutaneously introduced catheter guided to thetargeted ghrelin production sites using an imaging technique.
 16. Themethod of claim 15, wherein the imaging technique is selected from thegroup consisting of x-ray fluorescence or ultrasound tracking.
 17. Themethod of claim 1, wherein the embolic particles comprise a modifiedantisense oligonucleotide.
 18. The method of claim 17, wherein theantisense oligonucleotide comprises shRNA.
 19. The method of claim 17,wherein the antisense oligonucleotide comprisesghrelin-O-aclytransferase (GOAT).
 20. (canceled)
 21. The method of claim0, wherein the embolic particles comprising the antisenseoligonucleotide are delivered using a percutaneously introduced catheterguided to the targeted ghrelin production sites using an imagingtechnique.
 22. The method of claim 17, wherein the imaging technique isselected from the group consisting of x-ray fluorescence or ultrasoundtracking.
 23. A method of treating obese patients comprising: deliveringan embolic particle of a naturally occurring compound to arterialcapillaries feeding targeted ghrelin production sites of an obesepatient, the naturally occurring compound selected from one of amagnesium phosphate, a calcium di-hydrogen phosphate or a potassiumdi-hydrogen phosphate, and the naturally occurring compound dissolvingover time when introduced into the arterial capillaries: reducing bloodflow at ghrelin production sites using the embolic particles; andreducing production of ghrelin at the ghrelin production sites.
 24. Themethod of claim 23, wherein reducing production of ghrelin at theghrelin production sites comprises delivering antisense oligonucleotideto the ghrelin production sites.
 25. The method of claim 24, wherein theantisense oligonucleotide is embedded in the embolic particles and isdelivered over time as the embolic particle dissolves.
 26. The method ofclaim 23, wherein reducing production of ghrelin at the ghrelinproduction sites comprises delivering virus vectors to the ghrelinproduction sites.
 27. The method of claim 26, wherein the virus vectorsembedded in the embolic particles and is delivered over time as theembolic particle dissolves.